Perfomance problem for view list with many add to cart buttons

Hi.

I have a drupal commerce product view list with 30 products sorted by product name ASC and listed each with add to cart button.

AA
BB
CC
...
ZZ
...

Adding AA product to cart takes just 1-2 seconds, however adding ZZ Product to cart takes about 30 seconds !!!

Time does not depend on number of products in the cart, it depends only on product position on list. If I sort view by product name DESC - ZZ product on the top of the list becomes the fastest to add to cart and AA the slowest.

Add to cart buttons are displayed through views conditionl field. Is this a views conditionl field performance bug?

Any idea what has to be optimized so that adding any product to cart takes 1-2 seconds like it works without views conditional functionality?

Detailed description is in comment #7